Choanal atresia

Brian Wells, MPH, MSM

St. George’s University

Presentation available online at:

http://d.pr/TXSa

Preface to Presented Research

• "There is increasing concern that most current published research findings are false. The probability that a research claim is true may depend on study power and bias, the number of other studies on the same question, and, importantly, the ratio of true to no relationships among the relationships probed in each scientific field."

• Ioannidis JPA (2005) Why most published research findings are false. PLoS Med 2(8): e124.

Historical Background

• In 1755, Roederer first described congenital choanal atresia; therefore, this condition has been recognized for more than 200 years.

• In 1854, Emmert reported the first successful surgical procedure for congenital choanal atresia in a 7-year-old boy using a curved trocar transnasally.

• Over the years, the necessity of serial dilatations to maintain patency of the choanae has been clearly recognized.

Condition Overview

• Is obliteration or blockage of the posterior nasal aperture

• Often associated with bony abnormalities of pterygoid plates and mid-facial growth abnormalities

Etiology

• The nasal cavities extend posteriorly during development under the influence of the posteriorly directed fusion of the palatal processes.

• Thinning of the membrane occurs, which separates the nasal cavities from the oral cavity.

• By the 38th day of development, the 2-layer membrane consisting of nasal and oral epithelia ruptures and forms the choanae (posterior nares).

• Failure of this rupture results in choanal atresia. Although these choanae are not in the same location as the definitive choanae, which are eventually located more posteriorly, the unexpectedly anterior extent of choanal atresia is explained.

• In 2008, Barbero et al suggested that prenatal use of antithyroid (methimazole, carbimazole) medications was linked to choanal atresia.

Anatomy

• Boundaries of the atresia plate– Superior: sphenoid– Lateral: medial pterygoid lamina– Medial: vomer– Inferior: horizontal portion of the palatal bone

Nasopharyngeal Obstruction DDx

• Some causes in the newborn– Apert syndrome – Choanal atresia – Craniofacial anomalies – Crouzon syndrome – Macroglossia – Pierre Robin syndrome – Traumatic deviated nasal septum

Epidemiology

• Occurs in ~1 in 5,000 – 7,000 live births• More common in girls than boys• Approximately 2 out of 3 cases are unilateral

– More commonly right-sided• Slightly increased risk exists in twins. • Maternal age or parity does not increase the

frequency of occurrence. • Chromosomal anomalies are found in 6% of infants

with choanal atresia. Five percent of patients have monogenic syndromes or conditions.

• Choanal atresia occurs with equal frequency in people of all races.

Presentation

• Varies depending on whether one or both sides are involved

• Those with unilateral choanal atresia typically present later in life with– unilateral nasal discharge– And/or obstruction

• Bilateral – cyclic cyanosis relieved by crying• Unilateral – chronic nasal obstruction, thick

tenacious mucus

When to suspect?

• If a #5 or #6 French catheter cannot be passed from the nose to oropharynx a distance of at least 32 mm

• Qualitative measures of nasal airflow, such as the movement of a wisp of cotton under the nostrils or fogging of a mirror adds support to the clinical diagnosis

Diagnosis Confirmation

• Confirmed with CT with intranasal contrast that shows narrowing of the posterior nasal cavity at the level of the pterygoid plate

CT Scan Evaluation

• Choanal airspace measurement: mean normal is 0.67cm. Mixed atresia is 1/3 of normal, bony atresia measures 0.

• Vomer width – Mean 0.23cm, bony atresia mean 0.6cm, membranous atresia 0.3 cm.

Associated abnormalities

• May occur in isolation• May be part of a multiple congenital anomaly syndrome

– Treacher-Collins, CHARGE, Kallman, VATER association• (C)oloboma of the eye, (C)NS abnormalities, (H)eart

defects, (A)tresia of the choanae, (R)etardation of growth or development, (G)enital or urinary defects, (E)ar anomalies and/or deafness

• (V)ertebral anomalies, (A)nal atresia, (C)ardiovascular anomalies, (T)racheoesophageal fistula, (E)sophageal atresia, (R)enal and/or radial anomalies, (L)imb defects

• Other congenital abnormalities are present in 50% to 60% of individuals with unilateral and bilateral choanal atresia, respectively

Ancillary Services

• In addition to a through physical exam, cardiology and ophthalmology consults are indicated

• Associated anomalies include– Facial, nasal, or palatal deformities– Polydactylism– Congenital heart disease– Coloboma of the iris and retina– Intellectual disability– Malformations of the external ear– Esophageal atresia– Craniosynostosis– Tracheoesophageal fistula– Meningocele

Management

• Immediate management of infants with choanal atresia includes placement of an oral airway and initiation of gavage feedings

• Surgery indicated when conservative management is ineffective in sustaining adequate respiration and nutrition.

• Definitive repair involves transnasal puncture and stenting or endoscopic resection of the posterior nasal septum through a transnasal approach with or without stenting

• Transnasal puncture not favored due to high rate of recurrence

• Classic, transpalatal approach is reserved for difficult or recurrent cases

• Recurrent stenosis may occur even after successful surgery

Thank you!

Presentation available for download at:http://d.pr/TXSa